Plastic vacuum storage tank



Nov. 28, 1967 F. E. OBERMAIER 3,354,902

PLASTIC VACUUM STORAGE TANK Filed May 11, 1964 1/ Z r 55; J5 0 ZOa, Z9

BY q/ww %W INVENTOR.

United States Patent 3,354,902 PLASTIC VACUUM STORAGE TANK Frank E.Obermaier, Park Ridge, 11]., assignor to The Dole Valve Company, MortonGrove, Ill., a corporation of Illinois Filed May 11, 1964, Ser. No.366,282 1 Claim. (Cl. 137-496) This invention relates generally to acombined vacuum storage tank and valve assembly and more particularlyrelates to an improved fluid valve mechanism operative to accommodateflow through the valve in one direction while preventing backflow orleakage through the valve in an opposite direction.

Although the principles of the invention are of general utility, oneparticularly useful application is made to vacuum systems wherein avacuum pump or similar apparatus is utilized to withdraw fluid such asair from a given zone or machine such as a vacuum motor. It may benecessary or desirable in such systems to deactivate the vacuum pumpwhile maintaining a vacuum condition in the vacuum motor such as bypreventing the backflow or leakage of air to the motor. By means of thepresent invention, which may effectively serve as a check valve toprevent leakage of air back through the system, a vacuum may bemaintained over an extended period of time while the vacuum pump itselfremains inoperative.

The present invention is simple in design, easily constructed andassembled, inexpensive in manufacture, rugged, durable and adapted toserve a long, useful life. It is, therefore, an object of the presentinvention to provide a combined vacuum storage tank and valve assemblyfor utilization in a vacuum system capable of maintaining a vacuum inthe system over an extended period of time.

Another object of the invention is to provide a vacuum storage tank andcheck valve assembly wherein the valve member cooperates with anabutment wall of the tank to increase the sealing effect of the valvemember and to preclude leakage or backflow through the valve member.

Still another object of the invention is to provide a valve mechanismconstructed in a manner such that flow through the valve in onedirection is accommodated with a minimum pressure differential acrossthe valve while only a minimum reverse acting pressure differentialacross the valve will preclude bac-kflow or flow through the valve in anopposite direction.

Yet another object of the present invention is to provide a valvemechanism responsive to pressure differential thereacross for openingand closing the valve and wherein the pressure differential required tomaintain the valve in a closed position is reduced after the valve hasobtained a closed position.

Another object of the present invention is to provide a valve mechanismwhich is simplein design, is easily and inexpensively constructed andassembled and provides for improved sealing against back-flow.

Many other features, advantages and additional objects of the presentinvention will become mainifest to those versed in the art upon makingreference to the detailed description which follows and the accompanyingsheet of drawings in which a preferred structural embodimentincorporating the principles of the present invention is shown by way ofillustrative example only.

In the drawings:

FIGURE 1 is a vertical cross-sectional view of a combined vacuum storagetank and valve assembly constructed in accordance with the principles ofthe present invention;

FIGURE 2 is a side-elevational view of a diaphragm valve member whichconstitutes one important part of the invention; and

Patented Nov. 28, 1967 ice FIGURE 3 is a vertical sectional view of thevalve member taken substantially along lines IIIIII of FIG- URE 2.

As shown in the drawings:

Referring to FIGURE 1, reference numeral 10 indicates generally anillustrative embodiment of the combined vacuum storage tank and valveassembly of the present invention. One important usage of the inventionarises in connection with vacuum systems, wherein, a vacuum-producingmechanism such as a vacuum pump may be utilized to reduce the pressureof a fluid such as air in a particular zone or apparatus such as avacuum motor, and wherein it is necessary or desirable to maintain avacuum condition in such zone or apparatus for an extended period oftime after the vacuum pump has been deactivated.

In contemplation of such exemplary usage, the assembly 10 comprises atank body 11 which may conveniently be assembled from a pair ofvertically split halfportions 12 and 13 bonded together by means of aheat 7 seal at their mating edges 15, and which may, in its assembledform, assume the general configuration of a barrel. The body 11 may be,for purposes of economy of cost and weight, ease in construction andassembly and other considerations, be constituted of plastic materialwhich may be cut out at nonstrategic zones such as at 14 and 16 in orderto reduce weight as well as material requirements. In order to preventcollapse of the body 11 at high vacuum conditions, a plurality of ribsas at 15a are provided to strengthen and to rigidify the body. Formounting purposes a flange plate 17 is formed at the lower end of thebarrel-shaped tank, and a pair of slots as at 18 are formed in the'plateto receive respectively a mounting bolt or other suitable fasteningdevice.

In order to connect the tank 11 in a vacuum system a pair of connectornipples 19 and 20 extend from the tank body for connection,respectively, to a zone or apparatus in which a vacuum condition is tobe produced, such as a vacuum motor, and to a mechanism such as a vacuumpump effective to produce the vacuum condition. The connectors 19 and 20are tubularly shaped with slightly converging end portions toaccommodate easy connection to, for example, reinforced air hoses of avacuum system.

A vertically oriented annularly configurated cavity 21 is formed withinthe tank body 11 by mating annular recessed walls 21a and 21b formed inthe split sections 12 and 13. The annular cavity is, in turn,communicable with flow passageways 19a and 20a formed within theconnectors 19 and 20.

An outlet well 21c, defined by a cylindrical wall 22, is formed withinthe cavity 21 in surrounding relation to an inwardly extending boss 23,which boss has the innermost end of passageway 20a formed therein. Aflat annular shoulder is formed in surrounding relation to the wall 22and has and undercut annular groove 24 formed therein which groove isprovided to receive the peripheral beaded portion of a flexible annulardiaphragm later to be described.

A flat abutment wall 29 is formed integrally with the right hand halfsection 13 and presents a flat seating surface 31, which surface iscircumscribed by an annular raised ridge 32.

Situated within the well 210 substantially transversely to the directionof flow through such portion and effective to partition such portioninto a pair of divided chambers 33 and 34, is an annular flexibledisc-shaped diaphragm valve member 36. Referring to FIGURES 2 and 3, thevalve member 36 is more particularly characterized as comprising anouter annular rim portion or head 37, an enlarged central portion orprotuberance 38 and a Web 3 web portion 39 interconnecting the rim andthe central portion.

It will be noted that the" rim portion 37 comprises a back wall 40, aperipheral wall 41 and a front wall 42, and is shaped complemental tothe groove 28- (FIG- URE 1) and is fixedly supported thereby in theassembled position of the valve member 36, such as to produce in effecta seal bead around the valve member 36 to prevent leakage of fluid aboutthe peripheral edge thereof.

The central portion or protuberance 38 is generally frustoconicallyshaped and is axially forwardly offset in the direction of the abutmentwall 29, in its assembled position. The protuberance 38 is furthercharacterized as comprising a central axial aperture or passageway 43and a converging side wall 44 which terminates in a radially extendingwall member 46. A recess 47 is formed in the wall 46 such as to form araised annular sealing bead 48 encircling the aperture 43.

The web 39 is also forwardly inclined and comprises a front wall or face49, which blends into the side wall 4-4 of the protuberance 38, and arear wall or face 50, which blends into a rear wall 51 of theprotuberance 38. That portion of the rear wall 51 surrounding theaperture 43 forms a cylindircally shaped axially extending collar 52.

The valve member 36, or at least the web portion 39 thereof, constitutesflexible material such as rubber so as to accommodate axial movement ofthe protuberance or central portion 38. In the illustrated embodiment,the entire valve member 36 is made of rubber, thereby enhancing thesealing effect thereof between the valve and the engaging surfaces ofthe tank 11.

Asshown in FIGURE 1, a biasing member or spring 53 is housed within thecylindrical wall 22 in the chamber 33 and bottoms at one end thereof onan inturned portion 54 of the wall 22, and at the other end thereof, onthe rear wall 51 of the valve member 36 about the collar 52. The spring53 is constructed such as to impart a constant biasing force on thevalve member 36 in the direction of the abutment wall 29 so as to engagethe sealing bead 48 of the protuberance 38 into the face 31 of theabutment wall 29.

In operation, fluid such as air may be drawn through a bore 56 formed inthe inlet connector 19' from a pressurizable zone or apparatus such as avacuum motor and into the cavity 21 which forms a flow path to the well210. A pair of radially extending slots as at 57 are formed in theshoulder portion 32 of the abutment wall 29 to provide flow therethrough into the chamber 34 on one side of the valve member 36'.

Simultaneously, air is drawn from the chamber 33 on the opposite side ofthe valve member through a bore 58 formed in the outlet connector 20,and when the fluid pressure in chamber 33 is reduced sufliciently belowthat which exists in chamber 34, the biasing force of the spring 53 willbe overcome and the front wall 46 of the protuberance 38 will move awayfrom and become disengaged with the face 31 of the abutment wall 29.Thus, the fluid in chamber 34 will flow through aperture 43 of the valvemember 36, which is the only flow path across the valve member, and outthrough bore 58 to the vacuum pump or similar apparatus.

Upon deactivation of the vacuum pump, fluid pressure in chambers 33 and34 will become equalized and the spring 53 will again urge the sealingface 46 of the valve member into engagement with the face 31 of theabutment wall 29, and in this closed position, the valve member 36 actsas a check valve to prevent backflow or leakage from chamber 33 tochamber 34.

It will be noted, however, that in the closed position of the valvemember 36, as illustrated in FIGURE 1, the area of the face 50 of thevalve member 36 which is subject to fluid pressure in the chamber 33which pressure acts to urge the protuberance 38 axially into engagementwith the face 31 of the abutment Wall 29, is greater than the area ofthe face 49 of the valve member which is subjected to fluid pressure inthe chamber 34, by that area encircled by the seal bead 48 in engagementwith the face 31.

Accordingly, even when the pressure in chambers 33 and 34 is equalized,the seal bead 48 is urged by fluid pressure into good sealing engagementwith face 31 by a force which exceeds the force exerted by the spring53. However, when the vacuum pump again becomes activated and the valvemember 36 is moved to an open position, that is, out of engagement withface 31, the areas on both sides of the valve member 36 which aresubjected to fluid pressure in their respective chambers are equal,thereby reducing the pressure differential necessary across the valvemember to maintain the member in an open position.

Although minor modifications might be suggested by those versed in theart, it should be understood that I wish to embody within the scope ofthe patent warranted hereon all such modifications as reasonably comewithin the scope of my contribution to the art.

I claim as my invention:

A valve assembly comprising,

a body having a flow path therethrough,

an abutment Wall in said flow path,

a diaphragm supported at its periphery and disposed in said flow path,and

a coil spring engaging and biasing said diaphragm toward said abutmentwall,

said diaphragm comprising an outer annular bead, an enlarged centralportion and a web portion interconnecting said bead and said centralportion,

said central portion being axially forwardly offset in the direction ofsaid abutment wall, said central portion further comprising a centralaxial aperture, a converging side wall terminating in a radiallyextending wall member, and a recess formed in said radially extendingwall memher to provide a raised annular sealing bead encircling saidaperture substantially radially outwardly thereof, said web portionbeing axially inclined from said annular bead toward said centralportion and comprising flat parallel front and rear walls, said rearwall comprising a portion surrounding said aperture and forming acylindrically shaped axially extending collar for receiving one end ofsaid coilspring to center said spring against said diaphragm.

References Cited UNITED STATES PATENTS 1,910,961 5/1933 Perry 137525 X3,073,339 1/1963 Stelzer 137527 X WILLIAM F. ODEA, Primary Examiner. H.W. WEAKLEY, Assistant Examiner.

